DE2426120A1 - PROCEDURE FOR PERFORMING CONTINUOUS FERRING - Google Patents

Description

MTCNTAMSi (AtTE Λ ft Dr.-Ing. H.'NS RUSCHKE Z * May 1974

Dip «. · Ing. OL * F RUSCHKE Dlpi.-lng. HANS E. RUSCHKE

8 MUNICH 80 Bwutnautrftrae 2

Λ 1446 HER / Hr

ALFA-LAVAL AB S-14700 TUM3A / SCKWEDEK

Method of Conducting Continuous Fermentation

The present invention relates to a method for; Carrying out continuous fermentation in beer wort or in another suitable substrate, microorganisms being introduced into a circuit which comprises an elongated closed channel and into which the wort is continuously refilled. An advantage of such a method can be seen in the fact that the concentration of cell mass (microorganisms) in the wort can be kept high during the fermentation process, which leads to the desired high fermentation rate. However, it has been found that after a certain time the fermentation process ceases and for this reason the ancestor must be interrupted and the plant must be emptied and cleaned .

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With the present invention, the current process is improved in such a way that, in principle, no interruptions in the preliminary process are necessary if the fermentation process continues. According to the invention, this object is achieved in that the mixture of wort and cell mass is separated into three components after fermentation is complete, i.e. fermented wort, living cell mass and impurities, with fermented wort, impurities and the excess formed living cell mass is continuously discharged from the centrifuge. This allows the fermentation process to continue practically over an unlimited period of time. The explanation for this can be seen in the fact that the impurities, which have been shown to consist of dead egg cells and other excretions that are formed during the fermentation process, namely mainly proteins, accumulate in the circulation during the process as it was described in the introduction, up to a level such that their -. \ nwesenheit prevents the fermentation process, the reason for dieoe 'nsaminlung can be seen in the fact that when z L beer is produced by the discharge of cell mass from circulation makes up only 1 to 2 % of the cell mass,

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those in the Kreislau :? circulates. The possibility ~ e: .v '~ of the present 2rfindun> -;, the dead cells and impurities The reason for separating it from the living cell mass is that the impurities contained therein have a higher density than the living cells.

According to another aspect of the present invention centrifugation is carried out in such a way that the living cell ejected from the centrifuge: .iasr> e has a dry solids content of at least 10 percent by weight. The advantage of this is that it is it is possible to maintain a high cell concentration and consequently a low flow rate in the circuit without the difficulty of sedimentation in the channels of the plant. Through this the system can be made more compact and at the same time the mixture of wort and cell mass through the closed loop as a coherent plug pass through without running the risk that parts of the wort with different degrees of fermentation are mixed.

In addition, according to the present invention, cell growth in the circulation can be controlled by controlled Supply of oxygen, for example LuCt, to the living cell mass, ejected from the centrifuge v / ird, and more precisely this is what happens through it

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Then a separator is brought to derive a controlled mixture of fauerotof "" containing Os and lobing cells from the centrifugal solution. By controlling the oxygen flow, an optimal production is achieved of the product that is mainly to be produced by the process, such as beer or yeast. The monitoring or control is effected by a controlled throttling of the outlet of the separator. In this way, a controlled covering of the opening of the separator is achieved, and consequently a control of the ratio of gas to cell waste in the fish that is ejected by the separator. At the same time a remarkable intensive stimulation of oxygen-containing gas to the cell moisture is achieved.

The length of time of contact between the cell mass and the wort in the circuit can be controlled by. "Control of the intrusion by the lireislau, e.g. by controlling the supply of wort into the circuit. By means of this control can be ensured that the content of various gruelable sugars in the wort is used up to a sufficient extent will.

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Furthermore, according to the present ^ ^ rf.lndnn d''e Te: rf> oratur be controlled rning About Once-M by indirect ".vär-ie exchange au ^F various levels in different parts of ~ oschlossenen channel, in. -... \ t o'.no :: desired Ternperaturprogramm ^r 'o is ^ / ünschenswert that the temperature of fresh wort entering the circulation, is raised rapidly to a temperature such that the cells are active. Thereafter, the temperature in the course of the canal should be reduced to such an extent that optimal production conditions for the product are obtained, which in the first place is never desired poor development of the cells themselves, the fermentation process stops.

Falln the process used to make alcohol is to be, carbonic acid is suitably released at one or more points of the closed channel. because the foal acid pressure is too high on the one hand

hinders continued tariff growth and on the other hand which conjures up the danger that.part of the plant fail that are exposed to carbonic acid pressure ..

By the fermentation process is carried out in an elongated closed channel, it is possible to ^d: e to control fermentation, for example by adding the eradication of

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Enzymes or acid to adjust the pH '' places and the like in certain divisors, the closed Canals.

The closed channel also makes it possible to carry out fermentation at superatmospheric pressure. This can make the fermentation process run faster. The superatrnospn ^ rischo pressure can be produced by the formation of carbonic acid by ri'e 7 - Λ-len, and, if this is not sufficient, dry. ¹ - E "--.- pen of, for example, air, for example with hooves of a separator as mentioned before. The superat-ior, -pherical pressure can ^η 'η different parts of the TTar _: ⁿ l ~ at different levels being held.

The present invention is explained in more detail below with reference to the accompanying drawing; the Drawing shows a FIu ^ diagram of a 'plant,' ^ t the for example, the present method can be carried out.

A pipeline for supplying fresh wort is denoted by 1, and in this pipeline a pump 2 is provided, by means of which a predetermined "orge of wort per tent unit is introduced into the mixer Z , which is of a type that has no movable" ¹ G ¹ Ie

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BATH ORIGINAL

is working. In this mixer, the wort r "is it the customs mass gemiecht which is delivered h through the pipeline The mixture of wort and Zeil-;... .Iasr.e is from the mixer 3 to a spiral ^λ γ ä a ¹ Tn e exchange 5, where the mixture flows on a helical path inwards into a center, and ZAvar in countercurrent and under indirect flow exchange with an "odium, which flows through an equally helical path. The mixture ^r flows from the named center directly into a conduit 6, which leads to a helical reactor 7, where the mixture first flows in a helical path inwards to one center and then outwards from this center to another helical v, ^r eg. Ss will be no heat exchange in this helical? v.eaktor, which serves as a holding zone for the M is RECOVERY. The mixture is fed through a pump "from the reactor 7 through a line 9 to a helical. Heat exchanger 10 of the same type as the heat exchanger 5. The pump 8, which is known before." If it is red, foam or gas can separate out, such as excess air or carbon dioxide that has formed, and this gas is taken out via the pipe 11 by means of a pump 12, which creates a slight negative pressure. Pumps of the kind of

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Pumps 8 are arranged at the necessary points of the closed channel which is formed by the various helical heat exchangers and the helical reactors. It is possible to use a combination of an expansion vessel 13 and a pump 14 instead of a pump of the type mentioned. The gas released into the expansion vessel 13 is sucked out through line 11 and the mixture of wort and cell mass is then removed from the bottom of the vessel is pumped through a line 15 to eiro centrifuge 16. The mixture flows then from the helical heat exchanger 10 through a Le '..- tung 17 to a spiral-shaped reactor 18 from the same. ^A rt as the reactor 7. When this is necessary, v / urther assemblies of helical heat exchangers, and spiral-shaped reactors can be connected in series in the pipe 19, _How is indicated by the broken line. Since heat is generated by the cell growth, a cooling medium, for example cold water, is supplied to the helical heat exchangers through the lines, and the heated coolant is discharged through the line 21. The incoming mixture is divided in the centrifuge 16 into used wort, living cell mass and impurities (dead cells and precipitate). The wort, as the lightest phase, is taken up through a separating pipe 22 and out of the system as a whole

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a pipeline 23 discharged. The living cell mass as a phase of medium severity collects as the second outermost layer 24 in the mud chamber of the centrifugal joint rotor and is passed through pipes 25 into a central room 2.6, before it forms a circumferential layer 27. The living cell mass is removed from this layer through a pipe 28 and is for the most part returned through the line 29 to the plant. Only a small part, which corresponds to the proportion of living cell mass that was newly formed during the flow through the system, is removed via a valve 30, which keeps the pressure in the pipeline 29 constant. The impurities that were separated in the centrifuge collect as the heaviest phase in the outermost layer 31 in the sehlammraum of the centrifuge rotor and are discharged from there through openings on the circumference of the rotor, which either take the form of permanently open nozzles or normally closed openings are present, which are temporarily opened, for example by an axially displaceable, annular piston valve. It is possible to return part of the living cell mass to the centrifuge inlet 15 through a line 32, so that the cell mass then passes through the centrifuge at a desired high concentration. Tube 28 can be removed.

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The concentration in question can be set at the beginning of the procedure, but also during of the method by means of a control valve 33 which is located in the return line 32. In the preparation of of beer can possibly a part of the carbon dioxide from the pressure side 3 ^ - of the pump 12 over the line 35 can be passed under excess pressure into the beer, which is discharged through the pipe 23 will. This gives the beer the desired percentage of carbon dioxide, the level of which is determined can through valve 36.

When the procedure is initiated, the plant will first filled with a mixture of water and cellular maize, as already available through line 1 .is. After the centrifuge 16 by dewatering the mixture has raised the concentration of the cell mass to a fourth, which is necessary for stirring

ο of the process, the wort is about 20 C through the line 1 delivered. This wort gradually replaces the water in the mixture that is in the The system circulates until the wort concentration has reached a value that is necessary for operation is. The diluted wort, which previously leaves the system via line 23, can be drained go & eitet or to a suitable training

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processing. In order to avoid sedimentation in the channels of the AnInge, a certain flow velocity of the mixture must aui; Beer wort and cell mass are maintained. With a dry matter content of the table top of 15 % by weight, a speed of 0.1 m / sec. Is sufficient. If the dry matter content is below 10% by weight, flow speeds are above 0.3 m / sec. The canal system is designed so that the holding time in it is one to two hours, depending on the type of fermentation.The canal area should not be larger than 100 cm if the flow through the canals is to take place in the form of a coherent plug By adjusting the counter pressure by means of the valve JO , it is possible to cover the opening of the tube 28 in such a way that a suitable amount of Lu-Pt is mixed with the cell mass which is pumped out through the tube 28. When the opening of the Tube 28 is completely covered, an admixture of air to the cell mass is prevented, which comes into question with various types of alcohol fermentation, if the production of cell mass is the essential goal of the present method, it must be ensured that large quantities of air are sucked in through the pipe 28. An excess of cell mass, resulting in a corresponding

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Pressure rise in the pipe 28 is let out through the valve 30. · Due to the high concentration of living cells in the wort fermentation takes place quickly. By means of the various helical Heat exchangers in the fermentation canal can control the temperature in the different parts of the canal held v / earth. It is not only possible to cool but also to add heat - if that is required Oärungsverfahren makes this necessary. The different Places for evacuating gas, as shown at 8 and 13 is indicated, at intervals of 10 minutes (with reference to the reaction time) along the channel to be ordered. In addition, preferably at the inlets of the helical heat exchanger or the screw-shaped reactors various nutrient salts and enzymes or other additives are added that adjust the pH, thereby reducing the fermentation conditions can be adjusted in an optimal way based on the respective fermentation section.

Examples

1. Production of beer

The plant is filled with brewer's yeast that has been stored since the previous production phase.

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The IIefemasse, which has a dry matter content of around 15 wt / yr, already contains beer and wort and normally does not need to be concentrated before starting. If the IIefemass is contaminated, it is diluted with water and then passed through the centrifuge, whereby the washing water is separated and the channel system is filled with the cell mass. Beer wort of the desired composition and concentration, usually with an extract content of 8 to 16 wt / '. and a temperature of 10 to 15 ⁰ C, is entered into the circuit by means of the pump 2. The flow of the Ilefe mass is constant and has been adjusted by inserting suitable nozzles at the inner end of the pipelines 25. The flow should be adjusted so that the holding time for an Ilefe cell is one to two hours while passing through the fermentation canal, which is sufficient for the high cell concentration, which is at issue here. A flow velocity of about 0.1 m / sec. is necessary when the dry matter content of at IIefemasse etv / a 15 wt.% is. The amount of wort that is put into the circuit is thoroughly mixed with the yeast mass in the mixer 3. The ratio of wort to yeast mass should preferably be 1: 5 to 1:10. By changing the addition of wort, the holding time (fermentation time) can be set within certain

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Limits vary, but the Kauo! Setting is made by means of the He Teströrnunr; from the centrifuge. During fermentation, about 10 liters of carbonic acid are formed for every liter of wort, whereby this gas must be led out of the system, otherwise the gas because of its space requirements Reduces contact time and thereby interferes with fermentation. Preferably the channel is divided into sections, which, each corresponded to a contact time of 10 minutes, with cooling (heat exchanger) and removal of carbonic acid provided for each section. Chemicals, for example amino acids, enzymes or the like can be added during passage through the canal, increasing the quality of the finished Beer is controlled .. A control of the fermentation process can be carried out by measuring, for example the specific gravity or the amount of carbonic acid formed. Beer is made in the centrifuge separated in the clarified state under superatmospheric pressure, with a certain percentage Carbonic acid. Waste products formed such as secreted proteins, dead yeast cells and the like become deposited as a heavy phase. The yeast phase is separated by means of the separator tube and to the Returned to the cycle. The yeast growth is controlled

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by means of the counterpressure in the ileve outlet. Of the Back pressure is proportional to the coverage of the opening .Separator tube and inversely proportional to the air supply, thereby controlling yeast growth. As a result of the yeast growth, the pressure in the closed one decreases System closed, after which the valve 30 opens and releases excess yeast.

2. Manufacture of baker's yeast

In the manufacture of baker's yeast, sterilized helasses (and nutrient salts) are usually used as the substrate and the process is carried out in public as in the first example. Fermentation is aerobic and for this reason the greatest possible amount of air (or oxygen) must be added to the fermentation process in order to achieve a high yield. As already mentioned before, air is fed into the centrifuge by means of the sowing tube for the yeast mass. The plant works under superatmospheric pressure, with a large amount of air dissolving in the suspension of molasses and yeast. Air or oxygen gas can also be added elsewhere in the fermentation canal as well as nutrient salts, nitrogen, gas and the like. After the mixture of molasses and yeast a number of

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Holding portions has traversed, air, vemnre the vährend by gas development \ of this ^section: is nigt, aspirated and replaced with new air. Here, too, the cell concentration in the suspension is kept at a high level or at a dry mass content of around 15% by weight. Possibly wash water can be added at the end of the fermentation canal and it is then separated in the centrifuge together with the used molasses. The yeast formed flows off automatically through the valve 30.

-Patent claims-

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Claims (1)

- 17 claims •1. A method for performing continuous fermentation in a V ^r RIEF (substrate), wherein microorganisms are input to a circuit, - an elongate enclosed channel (5, 7, 10, 1Π) includes and is continuously inputted in the wort, characterized in that the mix of. '- ^r RIEF and cell mass (microorganisms) is divided by centrifugation after the fermentation has taken place in the circuit, in three components, namely fermented wort, living cell mass and impurities, wherein the fermented wort, the impurities and the formed excess of live Cell mass is continuously discharged from the centrifuge. 2. The method according to claim 1, characterized in that the centrifugation is carried out in such a manner that the living cell mass separated by the centrifuge has a dry matter content of at least 10% by weight. -18- 409885 / V370 - ίο - 2 ^ 26120 T), ancestors according to claim 1 or 2, characterized in that the cell growth in the circuit is controlled by the controlled supply of oxygen, such as air, to the living cell moisture, which is separated by the centrifuge, a separation device (28) for separating a controlled Mixture of oxygen-containing gas and living cell mass from the centrifuge is used. 4. The method of claim 1, 2 or. 3 characterized by that controls the contact time between the cell mass and the wort in the circuit is done by controlling the flow through the circuit, for example by controlling the inflow of wort to the cycle. 5. The method according to any one of the preceding claims, characterized in that the temperature by indirect heat exchange is set at different heights in the different parts of the closed Channel according to a specified temperature program. 6. The method according to einäm of the preceding claims for the production of alcohol -19- ■ 409885/1370 characterized in that carbonic acid in one or more places of the closed Channel is discharged. 7. The method according to any one of the preceding claims, characterized in that the fermentation by additives is controlled, for example with the help of enzymes, of acid to adjust the pH and the like at different parts of the closed channel. 8. The method according to any one of the preceding claims, characterized in that the fermentation is carried out at superatmospheric pressure. A-O 9885/1370 to Blank page